This invention relates to turn plate dirt seals, and especially to seals to exclude dirt from the bearings supporting the movable plate portion.
Automotive wheel supporting turn plates have been in existence for many years, and have included a base plate with a top surface acting as a race for bearings which support a top plate supplying the opposite race on its under face and presenting its top face for receiving the wheel. In operation, the turn plate allows a mechanic to place the wheel of an automotive vehicle upon the top plate in position for making it easy to turn the wheel while determining certain alignment characteristics. In turning the wheel the top plate must be free to move laterally as well as swivel, and this freedom of motion is obtained from the bearing means located between the base plate and the top plate.
If the turn plates are to function as intended, it is necessary to protect the bearing means and the bearing race surfaces against becoming fouled by dirt, and fluids which are accidently, or otherwise, spilled on the service floor. In many service areas, the attendant will hose down the floor and wash accumulated dirt, grease, oily substances, and the like into the turn plate. The result is that the bearing become pitted, the race surfaces become coated with foreign matter, and these two effects contribute to produce rapid wear and hard turning response.
The objects of this invention are to provide a dirt seal for turn plates to overcome the known problems in this art; to provide a seal that will not impare the desired function of turn plates; to provide a seal that will maintain the bearings and bearing races free of dirt and harmful matter, and to provide a seal that will remain effective for long periods of time and will be inexpensive to replace when necessary.
The embodiments of this invention comprise a base plate and a top plate having facing surfaces forming races, bearing means engaged on said races to support the top plate from the base plate and accommodate movement of the top plate, intermediate means between the top and bottom plates having an opening of a size to allow the motion of the top plate and any accompanying motion of the bearing means, and a dirt seal disposed in the opening and engaged on the races in position surrounding the bearing means to exclude dirt and foreign matter. The dirt seal may be fixed in position by the intermediate means or it may be carried by and move with the bearing means in the opening of the intermediate means.